First build, hopefully fast.

[LandSpeedRecord]

I see how you set it up Cannonball. That is a great set up and I could really benefit from that hub if it can hold up. That is definitely the best way to shift I have seen yet for a motorized bicycle. I keep thinking I need some sort of transmission and that is the first I have seen that makes sense. I am going to do some research on how much it can handle and probably go that way at least for the street. My compliments to the idea and build you have there.

 

[cannonball2]

So ran some figures through the gear calc and it looks promising. I don't know what your target engine rpms are and I don't mod CGs so have no real idea about how high a good one will turn so I used 8K as a base line. Using the same gearing I have for the hub but using a 26t(wow!) for a rear sprocket, the low range gear would get you to 61, and if I am thinking correctly the high range would top at 84mph. If you could get the poor little CG to turn 9K your top would be in the mid 90s.

Understand these are just gearing calculations. There are a million other factors that will determine the outcome. I don't know what the rules say about pedaling and its duration on start up. You would have gear the pedaling ratios to assist til at least the upper twenties/lower thirties. I believe the CG could begin to pull that ratio from 30 up. I geared my Ebike for pedal assist up to 28mph. You will be doing most of the work til at least the twenty mark I bet. Also understand that HP requirements jump exponentially from wind resistance as the speeds climb.
If you are shooting for one of the lower records then it gets easier.
Was just pointing out the gearing is possible. The rest is up to you!

 

[LandSpeedRecord]

I don't have a tach but the math says my CG spins around 10000rpm on flat ground. There are a few people that have spun them to 13000 but i don't think i could make more power doing that so no reason too. I actually want to gear and tune this set up to be between 8000 and 9000rpm at top speed, I not only need it to get there but hold together down the whole course at Bonneville. As you mentioned the power needed goes up in a curve so to double my current testing speed i need probably close to 4 times the power or more. That hub the way you have it would be a huge help. I was looking at my bike yesterday and the space between the seat tube and rear wheel is tight. I would have to mount the hub really high to fit it in there. Your bike looks like it would have vert little frictional losses and I need the same. I might have to cut the seat tube and fit it right in the center. Thanks for the ideasand calculations. I think i will end up doing this for sure, It's a matter of affording it too. If you don't mind me asking how much was yours and where did you buy it?

 

[cannonball2]

Mine cost $124 shipped as an open box special(was all there). The cheapest on ebay currently is $149.
Your frame is pretty much the same layout as mine. I dropped to 26" wheels to get feet flat on the ground. That opened up a bunch of space for the hub.
The speed calcs were based on a 26" wheel btw.
That's a pretty long hall at Bonnie. If you listen Bubfad mentions starting the second part of the two way run from mile ten. Im sure at his speed it took several miles to slow down. Still a run could be 10+ miles of CG torture. Get her sorted out real well!

 

[LandSpeedRecord]

You are very right Cannonball. It is a llllooooooonnnnngggg run at Bonneville. One of my thoughts was to cruise at say 50 or 60 until just past two markers to start the flying mile then twist it wide open. I will hopefully be able to find out in testing about how much distance it needs to reach top speed. I also am going to test holding it wide open for the amount of time it will take to cover the distance. I have some friends with a motorcycle dyno I may be able to sit on to simulate load over a few minutes, i would just have to aim a big squirrel fan right at the motor to simulate proper air flow. I found some pics of a 3 speed fixie show bike I helped with years ago with a hub Sturmey Archer custom built for us, i will post it later when i can get to a computer.

 

[LandSpeedRecord]

I am replacing the crank and clutch shaft bearings with high end ones in prep for heavy loads on the internals. Port matched the cases to the jug and did a lot more work on all the ports while it's all apart. I see the flow benefit of JB welding around the bearing areas and smoothing that area out but with the loads I will be putting on it I am afraid of the JB weld coming loose so I am not doing this step. If that area shows any signs of weakness I will have to weld it up and grind it down smooth in the future so it may happen in time. I have a double wound stator on order and a second rear mount block so hopefully with how it is going together it won't break again. I miss riding, I need to build a second bike to ride for the time this one spends in pieces, which seems like more often than not. OOOhhh the quest for speed ha ha. Happy motoring.

 

[LandSpeedRecord]

It's tough to get good shots inside the jug and ports but these give the idea.

 

[mapbike]

looking good.

 

[cannonball2]

If you are going really high compression I would advise helicoiling the cylinder stud holes in the case. If you have the room behind the engine at the rear mount you can run a second engine mount turned around backwards. Using this with a thicker metal backing plate and 1/4-20 hardened allens will keep the engine in place. I think the rear mount takes more of the load. You can do it on the front also if you drill out the mount holes slightly.

 

[LandSpeedRecord]

Yep, I will be putting heli coils in all the holes that take cylinder pressure and more. I ordered a second rear mounting block and am working on a way to attach the motor side mount to the cases in addition to having the bolts run thru it. I think i am going to try and make a third mount coming from the bottom bolt that hold the case halves together. I might also put a clamp around the sear tube just below the motor mount for extra support, i am tired of the rear mount breaking so going a bit overboard.

 

[cannonball2]

If you can weld or have it done, the lock collars would make killer mounts. They are not expensive($4/5 ea). If you want really stout mounts make a piece of 3/16 flat steel that is drilled to bolt to the engine then simply weld a collar to the top and bottom of the plate. They WILL NOT move. This assumes your frame has round tubing to mount to.

 

[LandSpeedRecord]

My seat tube is round, the down tube may have some shape to it but not much. I have to look at it close but I think the angle was off on the seat tube by 1 or 2 degrees which may have contributed to the problem. My second collar should be in tomorrow and I will start with the rear mount this time, make sure it is perfect and probably add to it. Then heat the front plate and bend it to match the angle of the tube. I have a lot of work to do before it is running again. I am building a set up to static balance the crank, more port work, press the new bearings in, I have a moto cross pipe I need to cut up and make fit. Then run it on gas for a while and if it all stays solid weld on the steering stops and steering dampener mounts and start testing the blended fuel set up. I would like to be at or above the salt records on pavement soon, so I hve time to get comfortably above them by August.

 

[cannonball2]

What type of fuel are you going to run?

 

[LandSpeedRecord]

I was building to run straight 15% nitro/methanol with castor. But I am now running a nitro R/C carb into the intake downstream of the main carb on 30% nitro/methanol with castor. I am adding a thumb throttle with a screw stop so I can refine and control just how much goes in. Nitro and gas seperate if left together but i am hoping the split second they travel thru the motor into the combustion chamber does not cause a problem. This is still on paper and a pile of untested parts but double carbs have been done using gas with success at least as far as operating. If it does not work as a power adder I will experiment running it on blended nitro using the formulas we use for the banshees.

 

[LandSpeedRecord]

I realized nitro tends to turn motors into many small parts flying in different directions so I am being extremely dilligent as to how much I feed it. I will start with the hopes that it can take 10% the cylinder pressure that a banshee can handle and work from there.

 

[cannonball2]

I ran nitro/methanol fuel in my open class kart. I also mixed my own fuel for some R/C applications. Is gas required for your class? If not why use methanol as the base fuel. A Tiliston would be an excellent carb. Bet there are some out there used already set up for similar cc engines.

 

[LandSpeedRecord]

They have separate gas and fuel classes. My goal is to possibly run both classes and have more chances. There are quite a few carbs that should work from chainsaws also as long as it's the versions with no rubber parts or fuel bulbs. My thought process with the r/c carbs is they are already nitro ready and the small ventury would keep velocity high, make tuning simple, and at 30% nitro blend be close to the amount of power i want to add. Thanks for the karting tip, those motors might be even closer to the CG at least in size than the banshee motors i was basing my comparisons off of.

 

[Flyman]

Hey Bud I,m flying out in a few weeks to Tucson & would like to meet up with you
& talk bikes. I that's possible let me know.

Fly

 

[cannonball2]

I have converted gas engines to run on glow fuel including some of the 4stroke trimmer engines. Judging by the increase in prop size they would turn I would guess at least a 30/40% increase in power. The issues with common glow fuel is the amount of oil. If you are running a hobby fuel particularly 30% heli mixes the oil is 22% or nearly 30oz!! I determined that the converted gas engines didn't need it and began mixing my own fuel using supplies from the local kart shop.
I found that a 31cc engine ran fine on a stock OS .90-1.20 2stroke carb. These are easy to find and fairly cheap.
I would seriously consider running a methanol/oil/nitro blend if injecting into the intake. The biggest advantage is the methanol will cool the engine somewhat while the nitro extracts the power from it. Not sure what nitro will do with gas only.
Not sure if E C Birt is still around but he and his son built some of the most awesome Tilly carbs going for methanol kart engines. I have the phone# somewhere. You just told them the engines specs and state of tune and they sent a carb with awesome performance beautifully flowed to the intake. Maybe you need two engines. A methanol engine would be awesome!

 

[LandSpeedRecord]

Correct, the nitro and gas wont mix. For my first try I plan my normal 50 to 1 synthec gas oil mix going thru the main carb and 30% nitro/methanol with castor being fed thru an r/c carb that enters down steam of the main carb. I plan to drill a hole at a shallow angle and run an aluminum tube into it the size needed to attach the r/c carb. I will mount a nitro r/c tank behind the seat to hold the fuel. The nitro will be it's own independent system with a thumb throttle.